Challenges and choices for the decarbonisation of maritime transport
DNV's Transport in Transition report presents the next steps in the decarbonisation of maritime transport. Paul Adrian, President of Adinergy, gives us a summary of this report.
Due to its international dimension, the maritime sector is subject to global standards and regulations. In 2018, the IMO set the objective of reducing greenhouse gas emissions by 50% compared to 2008 levels. These requirements are expected to be further strengthened in 2023 with an increased target to fully decarbonise the sector by 2050.
An electricity-consuming sector
As for the other sectors of the economy to be decarbonised, the transport sector and the maritime sector in particular will be major consumers of electricity in the near future.
Hydrogen, ammonia and e-Methanol will be produced from green electricity in order to decarbonise the maritime sector.
Maritime in the ETS in 2024
The European Union is the only major regulator, alongside IMO, to impose greenhouse gas (GHG) emission requirements on ships. Indeed, the Emissions Trading Scheme (ETS) is expected to include shipping in 2024. To achieve these objectives a large number of national and regional policies exist as well as initiatives from all stakeholders.
Electrification, a partial solution
Electrification of the maritime sector will only be possible, with the current state of battery technology, for ship calls and coastal or inland navigation. International maritime transport must find other solutions with higher energy density.
A basket of solutions
A basket of solutions will therefore be implemented. Firstly, the transfer of fuel from oil (MGO/HFO) to gas (LNG) will have a significant impact on the sector's GHG emissions. Secondly, speed reduction, voyage optimisation, sail propulsion, on-board CO2 capture and storage and energy efficiency improvements of ships will all contribute to achieving the targets.
A 70% reduction in some emissions already underway
The reduction of sulphur in MGO that came into effect in 2020 has already resulted in a 70% reduction in sulphur oxide emissions from shipping, according to IMO figures. This has fundamentally changed the type of fuel used by ships and the fuel mix will only increase over the coming decades.
Fuels of the future
Perhaps the most important step towards carbon and greenhouse gas neutrality will be the development of alternatives to fossil fuels. Bio-fuels, produced from biomass, i.e. organic matter that can become a source of energy, would be the ideal fuel for maritime transport. Indeed, they can easily be converted into bio-MGO or bio-LNG with high energy density. In view of the volumes required and considering the fact that these bio-fuels will be demanded by all modes of transport (road, air and sea), it would appear, however, that feedstock would not be available in sufficient quantity. Thus, competition between modes will increase prices and make the availability of these fuels more uncertain. This competition on bio-fuels would then make e-fuels competitive and able to be produced in sufficient quantities for shipping.
Hydrogen derivatives
Because of its low energy density, hydrogen in its pure form is unlikely to find its way into ship engines. However, hydrogen derivatives such as ammonia and e-methanol will develop and cause a strong increase in demand for green hydrogen (both fuels are produced from hydrogen).
Interest in ammonia
There is a lot of interest in ammonia. This is because it is a zero CO2 or GHG emission fuel. It is also easier to store than hydrogen. However, ammonia-fuelled engines are not a mature technology. The main challenge is safety, as ammonia is a highly toxic product. However, it is a product that is transported and stored for other usages. The infrastructures therefore exist and could be used in ports to supply ships.
Methanol, an alternative to ammonia
Unlike ammonia, which must be stored at -33°C or pressurised to 10 bars at normal temperature, methanol can be transported and stored at ambient temperature. This alcohol is said to reduce SOx and NOx emissions by 60% and particulates by 95% compared to HFO. Another advantage of methanol over ammonia is that methanol can benefit from the storage and bunkering infrastructure of the European Union.
Low flash point
Moreover, it is simpler and less dangerous to use than ammonia. It is therefore a serious alternative to ammonia, provided that e-methanol is produced from decarbonised sources. The challenge with methanol is its very low flash point: 11°C compared with 60°C for conventional fuels, which represents a major risk that will require appropriate safety measures, including fire detection systems, as its flame is invisible.
The role of electricity
Although not very applicable to international shipping, electricity will play an important role in decarbonising the maritime sector by supplying ships calling at ports. This electrification, which is already underway in some ports, allows for the reduction of pollution generated by ports which are most often located in densely populated basins.
Electricity on inland waterways
For the same reasons, the electrification of river transport should allow the development of this mode of transport which is an alternative to road or rail and allow a more balanced distribution between these three modes and these three infrastructures. A battery exchange and standardisation system is being developed which would reduce the downtime of vessels.
Renewable energies will not be enough
This sharp increase in demand for electricity, a single source of energy, does not yet seem to have been taken into account by European governments, which are closing nuclear power stations here and there and reactivating coal-fired power stations. Renewable energies, which are essential contributors, will not be enough because of their intermittency. Clean, controllable sources of electricity production are also essential. The real challenge starts here
This article is the english translation of the french version published on web site: Ports et Corridors